Satellite altimetry data indicates that the rate at which the world's oceans are rising has slowed significantly since 2005. Before the decrease, sea level had been rising by more than 3mm/year, which corresponds to an increase of about one foot per century. Since 2005, however, the rate has been closer to 2mm/year.

The decrease is significant as global climate models predict sea level rise to accelerate as atmospheric CO2 continues to increase. In the 1990s, when such acceleration appeared to be occurring, some scientists pointed to it as confirmation the models were operating correctly.

Sea level rise was calculated from altimetry data from the TOPEX/Poseidon and Jason-1 satellite missions, published by the University of Colorado, Boulder.

Dr. James Choe, a research associate with the University of Colorado, says the decrease is temporary. "Interannual variations often cause the rate to rise or fall", he says. Choe believes an accelerating trend will reappear within the next few years. Oceanographer Gary Mitchum of the University of South Florida, says making any judgement from the limited data available is "statistically so uncertain as to be meaningless".

Others disagree. Dr. Vincent Gray, a New Zealand based climatologist and expert reviewer for the IPCC, believes that the accelerated trends seen earlier were simply an artifact of poor measurements. "The satellite system has undoubtedly shown a rise since 1992, but it has leveled off", he tells DailyTech. "They had some bad calibration errors at the beginning."

Gray points to a study done by Flanders University using tide gauges which, he says, measured no perceptible increase in sea level over its entire 15 year period.

Sea level has been rising since the end of the last ice age, some 20,000 years ago. During an episode known as "Meltwater Pulse 1A", the world's oceans rose by more than 5 meters per century, a rate about 20 times faster than the current increase.

TOPEX/Poseidon was launched by NASA in 1992, and collected data until 2005. In 2001, NASA and France's Centre National d'Études Spatiales (CNES) launched its follow-up mission, Jason-1.

Jason-2 was launched in June of this year.

Comments

Threshold

Username

Password

remember me

This article is over a month old, voting and posting comments is disabled

I choose to believe in the Prisoner's Dilemma. If we do something about it and climate change is indeed influenced heavily by man, then we will have spent billions of dollars but for a good reason--saving countless species from extinction as well as keeping the progress of the human race steady without catastrophe. If we do something about it and climate change is just cyclic and humans have little to no effect, then the tens or hundreds of billions of dollars we will have spent may very well seem like an outrageous waste, but alas the haze of pollution is nearly gone and our technology has progressed due to intensive research and development.

Now if we DON'T do something about it and climate change has little to nothing to do with human activities, then we are no worse than we are at the moment and everything is fine and dandy. We have gained nothing but we have also lost nothing. If we don't do anything about climate change and it is indeed heavily impacted by human activities, then we are in quite a lot of trouble my friend. Massive amounts of refugees from islands and low-lying areas, disease progression, dramatically different weather (droughts or floods), the loss of countless species and the overall hardship that will be incurred on civilization.

Personally, I think it is best to try to move ourselves toward cleaner, renewable and efficient technologies and reduce what impact humans might have on the atmosphere. Face it, we are still a young civilization and there are many things we don't know and many things we can't accurately predict. What if global cooling returns? Will we start to pump CO2 back into the atmosphere if that will help? What if global warming escalates faster later down the line and we didn't cut our greenhouse emissions fast enough? Will we deploy radical concepts such as sunshades or carbon capture?

Time will tell. For now, I choose to be on the side supporting the switch to renewable energy. If not for anthropogenic climate change then for the progress of science and technology and the energy independence of the United States of America.

quote: if we DON'T do something about it and climate change has little to nothing to do with human activities, then we are no worse than we are at the moment

Wrong. We won't have spent "billions", we'll have spent hundreds of TRILLIONS of dollars. You know how many lives we could save with that money?

You think changing out your light bulbs and driving a hybrid is all these carbon-trading proposals are all about? They will make anything and everything that creates or uses energy much more expensive. That's every single product and service. I seem to remember a story here about the UN estimating it would cost $47T (that's a "T", not a "B") just to get the ball rolling. I've seen other estimates a lot higher.

Hundreds of trillions of dollars? Very doubtful we'll spend that kind of money being as it is tens of times more than the entire yearly GDP of the United States. Also I said if we DON'T do something (as in we don't invest any money into trying to fix this apparent problem) then we are not in any worse shape because this whole climate change thing was just erroneous to begin with--meaning we overreacted to observed data.

Oh and I didn't mention specifics anywhere. If we don't do anything about it we may still switch from incandescent to compact fluorescent to increase energy efficiency. But I think you fail to understand that new technologies are almost always more expensive than the old technologies because we have to figure out the best ways to mass manufacture these technologies while minimizing the cost of materials needed for those products. Any sort of change requires upfront cost.

At the very least, our change from incandescent to fluorescent and internal combustion only to hybrid or alternative fuel engines comes from necessity in that the demand is exceeding available supplies and their are severe geopolitical strains placed around the world due to such limited and highly valuable resources (fossil fuels). By switching from fossil fuels to renewable fuels we effectively eliminate such geopolitical tensions caused by the need for energy. We are a growing civilization and will depend on high efficiency if we are to continue to stay here on the planet Earth while having somewhat limited off planet activities (i.e.: no major mining activities in the solar system). Heck, even if we have major operations in space, we will still demand efficiency in order to be cost-effective and prevent a possible stagnate in progression of our civilization.

quote: Hundreds of trillions of dollars? Very doubtful we'll spend that kind of money being as it is tens of times more than the entire yearly GDP of the United States.

Opportunity costs, and not just in a single year, but compounded over a century or more. Using a number like 10%, it's extremely easy to compound in to numbers in the high trillions by 2100. Using a lower number, like 6%, isn't quite as easy, but lets just say we toss 100b down the global warming hole this year that ends up being completely wasted because it turns out we were wrong, but no more is spent in the future. By the year 2100, thats 21.29 trillion in foregone investment in productive areas of the global economy.

I put nothing past the stupidity of the UN and Obama. He already wants to spend the better part of a trillion dollars on giving money to the poor in other nations. Because we're somehow responsible for making other nations less poor.

Obama as president in a time where the UN is constantly trying to act like it has legislative and executive authority over the US is a scary thought. The problem is its not just a thought.

This past year has already put taxpayers on the line for $7-8 trillion dollars of NEW debt in the long term. Not even repealing the Bush tax cuts is going to pay for that. Plus Obama wants a MANDATORY 5% "savings plan" coming out of your check that is on top of Social Security. It would be your own private account but the government has access to it to borrow from. So in essence it will be badged as a way to make Americans save so they don't have to rely on Social Security. But ol' grandpa government will be able to borrow against it just like Social Security so the money will disappear. Expect your paychecks to go down in a big way. And with employers freezing salaries, you won't have a raise to offset it. We just found out yesterday at my company that we're not getting raises.

My only hope is that the Republicans will make the next 2 years hell for Democrats by filibustering every socialist policy they bring up. I don't care if that means the government gets effectively shut down. It's better than the alternative.

"If you look at the last five years, if you look at what major innovations have occurred in computing technology, every single one of them came from AMD. Not a single innovation came from Intel." -- AMD CEO Hector Ruiz in 2007